Clinical evaluation of four amalgam alloys: a five-year report.

In this study 96 teeth of 12 patients were restored with either the conventional alloy Premix, the blended non-gamma 2 amalgam Dispersalloy, or one of the spherical alloys Sybraloy and Tytin. To ascertain an objective comparison of the clinical performance of these alloys, two different alloys were used in each of at least two dental arch quadrants in the same patient and consequently were placed in the same oral environment. Clinical performance of the restorations was evaluated by macrophotography and scanning electron microphotography of replicas made after placement and 2, 3, and 5 years thereafter. Standard criteria were used for the evaluation of anatomic form, surface condition, and marginal adaptation of the fillings. In addition, the filling-enamel interface was assessed from the microphotographs. The three high-copper alloys performed better clinically than the conventional alloy, and the spherical alloys had the best qualifications. In addition to visual examination and photographic evaluation of restorations, the micrometric assessment of replica photographs from the scanning electron microscope may render clinical trials of amalgam alloys measurable and less subjective.

Mantle dentine in man--a quantitative microradiographic study.

50 microradiographs taken in a standardized manner of midsagittal ground sections of teeth of individuals aged 18 to 56 years were densitometrically evaluated along a track passing through enamel, dentine and an aluminium stepwedge. Semi-quantitative analysis of mineral density uniformly showed an irregular platform representing circumpulpal dentine and a peripheral down slope in the region of the amelodentinal junction, representing mantle dentine. The width of this less mineralized peripheral zone measured on densitometric recordings averaged 150 microns (+/- 50). Quantitative analysis of the two dentinal regions permitted the calculation of the mineral content in terms of volume percentage using both a graphic method and an electronic computer method. The sections were also examined by polarized light microscopy which clearly visualized the presence of peripheral mantle dentine. The mean mineral density of circumpulpal dentine was 46% according to both the graphic and the computer methods; mantle dentine yielded means close to 42% according by both methods. The 4% difference in density between circumpulpal dentine and mantle dentine proved to be statistically significant; there was no significant difference between the means obtained graphically and those obtained electronically. The need for further investigation of this region of the amelodentinal junction was stressed.

Ultrastructure (SEM) of dentine bridging in the human dental pulp.

This study was designed to investigate by SEM the ultrastructure of the dentinal bridge formed upon pulp capping and its attachment to the contiguous dentinal walls. The pulps of 20 sound premolars and third molars were deliberately exposed and capped with a calcium hydroxide paste, Pulpdent. After 4 to 15 weeks the teeth were extracted. SEM observations suggested complete bridging, increasing in thickness after succeeding postoperative periods. Cross-sections of the specimens older than 6 weeks showed the presence of three different layers within the bridges: the superior amorphous layer was composed of tissue debris and Ca(OH)2, in the medial portion a coarse meshwork of fibers was identified as fibrodentine and the pulpal aspects exhibited tubularlike orthodentinal structures. The bridge attachment was secured by bundles of fibres linking the intertubular dentine of the pulpal walls with the dentine of the neodentinal bridge.

The adaptation in various languages of standardized periodontal terminology to recent acquisitions.

Before nomenclatorial translation can be begun, an approved definition of the term concerned is required, as is a systematic classification of related designations. Existing sources are bi- or multi-lingual dictionaries and glossaries but relatively few of these cover oral biology and dentistry in adequate detail. Much of the terminology developed for specialized fields of medicine is applicable to dentistry in general and periodontology in particular but the proliferation of new terms in English/American cannot always be matched appropriately in other languages. Examples of a uniform periodontal terminology in English, French and German--prepared for the impending revision of the FDI Dental Lexicon--are tabulated.